# tdgrid

Draws a grid on a particular face of a box in 3-space (for use with selected TDPACK routines).

*Available in version 4.3.1 and later.*

## Prototype

procedure tdgrid ( wks [1] : graphic, xbegin [1] : float, xstep [1] : float, nx [1] : integer, ybegin [1] : float, ystep [1] : float, ny [1] : integer, grid_flag [1] : integer )

## Arguments

*wks*

An NCL workstation identifier for where you want to draw the surface.
The *wks* identifier is one returned either from calling
**gsn_open_wks** or calling create to
create a Workstation object.

*xbegin*

*xstep*

*nx*

*xbegin* and *xstep* are float scalars that define where
ticks or grid lines are to be drawn along the X axis of the
parallelogram. *nx* indicates how many ticks/lines to draw
(*xbegin*, *xbegin*+*xstep*,
*xbegin*+2**xstep*,
... *xbegin*+(*nx*-1)**xstep*).

*ybegin*

*ystep*

*ny*

*ybegin* and *ystep* are float scalars that define where
ticks or grid lines are to be drawn along the Y axis of the
parallelogram. *ny* indicates how many ticks/lines to draw
(*ybegin*, *ybegin*+*ystep*,
*ybegin*+2**ystep*,
... *ybegin*+(*ny*-1)**ystep*).

*grid_flag*

Integer flag that defines what is to be drawn: 1 (draw just a perimeter), 2 (draw a perimeter with inward-pointing ticks), or 3 (draw a perimeter with a grid).

## Description

This routine is part of the low-level TDPACK package, which is a group of Fortran and C callable routines for projecting objects from a 3-dimensional coordinate system having U, V, and W axes to a 2-dimensional projection plane having X and Y axes and/or for drawing the projections of those objects. This can be referred to somewhat loosely as "drawing objects in three dimensions".

This procedure draws a perimeter, optionally with ticks or grid lines,
around the edges of the reference parallelogram defined by the last
call to **tdpara**. This routine is normally called
indirectly (by virtue of a call to **tdgrds**), but
there is no reason why it should not be called directly.

Please see the documentation on TDGRID for a full description of this procedure.

## See Also

Initialization routines:
**tdinit**,
**tdpara**,
**tdclrs**

Parameter access routines:
**tdgetp**,
**tdgtrs**,
**tdsetp**,
**tdstrs**

Point transforming routines:
**tdprpt**,
**tdprpa**,
**tdprpi**

Line drawing routines:
**tdline**,
**tdlndp**,
**tdlnpa**,
**tdlpdp**,
**tdcurv**,
**tdcudp**

Grid drawing routines:
**tdgrds**

Label drawing routines:
**tdlbls**,
**tdlbla**,
**tdlblp**,
**tdplch**

Surface drawing routines:
**tddtri**,
**tdstri**,
**tditri**,
**tdmtri**,
**tdttri**,
**tdctri**,
**tdotri**,
**tdsort**

Simplified interface routines:
**tdez2d**,
**tdez3d**

## Examples

No examples for this routine are available at this time.